Drum of a washing machine

ABSTRACT

A drum of a washing machine comprising a cylindrical band, at least two rows of openings defined on the cylindrical band, arranged along a central line between both of them, and at least a blade with a blade base from which at least two corresponding rows of couplings extend, which are fittable into said openings to fasten the blade to the cylindrical band in an interior of said drum.

The present invention relates to a drum of a washing machine for a washing machine, dryer or the like, of the drum type, comprising a cylindrical band, at least two rows of openings defined on the cylindrical band, arranged along a central line between both of them, and at least a blade with a blade base from which at least two corresponding rows of couplings extend, which are fittable into said openings to fasten the blade to the cylindrical band in an interior of said drum.

The use of a washing machine of the rotating-drum type is generally known. In these machines it is usual to utilize a number of, for example three or four, agitating blades projected inwards in the interior of the drum so as to make articles being washed spin during the washing and rinsing operations. Patent GB1161219 illustrates a plastic blade with a substantially triangular cross section with closed ends in order to have a U-form fixed to the drum interior by means of projections, which extend from the blade edge and are held in two rows of cooperating L-slots on the drum wall. The projections are inserted into a wider zone of the L-slot and slide over a narrower zone. In order to interlock them, the blade is screwed on the drum band. A problem of this arrangement of projections consists in the fact that it does not have an immediate interlock between the blade and the drum available and requires an additional joint to fix it. When securing the blade to the cylindrical wall of the drum by means of the projections arranged at the tub edges which fit into the cooperating L-slots on the wall, another fastening element such as a screw will obviously be necessary, as it is described in the prior art, to keep the blade in position after fitting it onto the wall since the projections could just get out of the slots.

Patent application ES_(—)2276627_A1 shows a drum of a washing machine comprising a cylindrical band, and at least a blade fastened to the cylindrical band in the interior of said drum by means of two corresponding rows of elastic couplings, which extend from the blade and are held in receptacles at the cylindrical band of the drum. The receptacles have a protuberance extending into said receptacle so as to slide said elastic couplings by flexing them, and a fastening part to secure said couplings. This type of blade coupling continues needing an additional fastening means, since the couplings still have clearance and may vibrate producing noise if they are not additionally fastened to the band when the receptacle flexes the couplings and a second zone of the receptacle is entered.

As a consequence of this, it is the object of the present invention to offer an improved drum of a washing machine in which the openings may secure and retain the blade couplings in position respectively, even without the aid of the fastening elements such as fixing screws, rivets, etc.

Another object of the present invention is to offer a drum of a washing machine with blades with no potential relative movement between them and the drum to reduce the noise made by this movement.

According to the present invention, the above-mentioned objects are achieved with an improved drum of a washing machine comprising a cylindrical band, at least two rows of openings defined on the cylindrical band, arranged along a central line between both of them, and at least a blade with a blade base from which at least two corresponding rows of couplings extend, which are fittable into said openings to fasten the blade to the cylindrical band in an interior of said drum, wherein at least one opening has a cut-out extending outwards from the opening, and at least one coupling has a rigid element joint to the blade base at a first end and an elastic retaining element at the rigid element fittable into the cut-out in the position of blade mounted on the drum.

According to other characteristics of the present invention, at least one coupling has at least one flap at a second end of the rigid element contactable with a surface of an exterior of the cylindrical band in a position of blade mounted on the drum.

The central line between both rows is substantially parallel to the drum rotation axis.

The opening has a bigger area which is big enough to be crossable by the coupling in a position of dismounted blade, and a smaller area where the cut-out is located, which is big enough to surround the first end of the rigid element contacting it in the position of blade mounted on the drum.

The cut-out includes a cross section substantially of a triangle and a rectangle.

The blade also comprises a hollow body opened towards the band at the blade base and a plurality of inner ribs located inside the body.

At least one screw hole is defined at one end of one of said ribs, wherein a screw is housable in a corresponding opening defined on said cylindrical band in case any coupling breaks and the blade needs to be secured.

Additionally, a tab is provided extending inwards from said cylindrical band and is fittable with one of the ribs, additionally securing thereby the blade to the drum in its longitudinal movement.

Furthermore, a plurality of outlets is defined on a top side of the blade to obtain a rain effect in the washing process.

The total length of the blade is smaller than a distance between two circular end walls of the drum so that it may be mounted by displacing it in the central line direction from the non-mounted position to the mounted position.

The blade is made of plastic, what simplifies and makes its manufacture cheaper.

When the blade is mounted on the drum, the blade couplings are inserted through the openings' bigger area in a non-mounted position and are slid towards the opening's smaller area by flexing the elastic retaining element until this fits into the cut-out without the need for the coupling to flex. The coupling's connection body may be rigid and strong from its base up to its end, so that it does not break and has no clearance in the opening's smaller area to prevent the blade from vibrating and so that they are fastened firmly at the openings' fastening part respectively. With this configuration of blade couplings, it is avoided that the blade moves backwards or dismounts. The additional flap may be arranged at a coupling with o without an elastic retaining element.

The figures show:

FIG. 1 is a perspective view of a blade and the part of the washing machine drum on which it has to be secured;

FIG. 2 shows a detailed perspective view of a coupling of the blade according to FIG. 1;

FIG. 3 shows a section of a blade with a side view of a coupling according to FIG. 2;

FIG. 4 shows the mounting positions of a coupling of the blade before being coupled and being coupled;

FIG. 5 is a perspective view of the blade set mounted within a washing machine drum.

With reference to FIG. 1, a washing machine drum 1 for a washing machine, dryer or the like, of the drum type comprises a cylindrical band 2 and at least a blade 3 fixed in an interior of the drum 1. At least two rows of openings 4 are defined on said band 2 to receive correspondingly two rows of couplings 5 which extend from the blade 3. If the blade is of a small size in the form of a tooth, it may have even only a coupling 5 that fits into an opening. In the present embodiment, blade 3 is long with two rows of couplings, one on each side of a central line 6 parallel to the rotation axis of drum 1, the same number of openings being defined on both sides of the central line 6, although this is not necessary. Alternatively, the central line 6 may not be parallel to the drum rotation axis, whereby a different number of openings may be defined on both sides of the central line 6 provided that the openings 4 defined on the band 2 comply with the requisites regarding mechanical property to fasten the blade 3 to the band 2 reliably.

FIG. 2 shows a perspective view of a part of the blade where the coupling is located. On the blade base 12 which is closest to the drum in mounting position I (FIG. 4), the couplings 5, which have a rigid axis 52, project from the one end up to their other end, the latter ending in a flap 53 which contacts the outer face of the drum band in the blade's mounted position II (FIG. 4). An elastic retaining element 51, which may be bent by applying a force, projects from the coupling's rigid part 52.

FIG. 3 shows a side view of a coupling, wherein you may observe the slot between the coupling flap 53 and the blade base 12 where the drum band is introduced.

With reference to FIG. 4, each one of the openings 4 also comprises a cut-out 7 projecting outwards at each one of the openings 4, dividing each one of the openings 4 into a bigger area 41 which is big enough to be crossable by the coupling 5 in a position of dismounted blade II, and a smaller area 42 where the cut-out 7 is located, which is big enough to surround the first end of the rigid element 52 of coupling 5 contacting it in the position of blade mounted on the drum I. The opening edge forms at its bigger area a slope ending in the cut-out 7 to facilitate that the elastic retaining element 51 bends until it is inserted in the cut-out. Said cut-out 7 includes a cross section of a triangle and a rectangle which follows the form of the elastic retaining element 51 and where, in a mounted position II, the elastic retaining element 51 of the coupling 5 fits in.

As it is shown in FIG. 1, blade 3 also comprises a hollow body 10 opened towards the cylindrical band 2 at the zone where the blade 3 is fastened, a plurality of parallel inner ribs 11 located in the hollow body 10 to increase the rigidity of blade 3 and an end of each inner rib 11 having a blade base 12 which extends from an interior of blade 3. When the blade 3 is mounted on the drum 1, the openings 4 will be covered with the blade base 12 respectively. Preferably, at least one screw hole 13 is arranged at one end opposed to the blade base 12 of the inner ribs 11 to house a fixing element, such as a screw, in a corresponding opening 16 of the cylindrical band 2 with the aim of obtaining a better fixation of blade 3 on the cylindrical band 2 in case any coupling breaks due to its use. Furthermore, at least one tab 14 extends inwards along one of both rows of openings 4 to fit with one of the inner ribs 11 and prevent blade 3 from moving backwards once mounted so as to reinforce the joint, should this be necessary.

Furthermore, in order to obtain the so-called “rain effect”, meaning that, after having been led upwards by the blade 3, the water falls in a shower manner in an improved way so as to wet the washed articles, a plurality of outlets 15 is arranged on a top side 17 of blade 3, as it is shown in FIG. 5.

Furthermore, as it is shown in FIG. 5, the total length L′ of blade 3 is smaller than distance L between two circular end walls of drum 1, whereby it is no longer necessary to retain articles which are being washed.

It should be understood that, despite the fact that many characteristics and advantages of the present invention were disclosed in the preceding description together with details regarding the structure and function of the invention, the description is merely illustrative and detailed modifications may be introduced, in particular in aspects related to the shape, size and arrangement of the parts, within the scope of the principles of the invention and determined to a great extent by the broad general meaning of the terms used in the enclosed claims. 

1-10. (canceled)
 11. A drum of a washing machine comprising: a cylindrical band with a row of openings on each side of a central line; and a blade with a base and two rows of couplings extending from the base which are receivable into the rows of openings to fasten the blade to the cylindrical band in an interior of the drum, wherein at least one of the openings has an outwardly extending cut-out and wherein at least one coupling has a rigid element joined to the blade base at a first end having an elastic retaining element fittable into the cut-out when the blade is mounted on the drum and wherein the rigid element has a flap at its second end that contacts an exterior surface of the cylindrical band when the blade is mounted on the drum, wherein the at least one opening further includes an area that is big enough to be crossed by the at least one coupling when the blade is not mounted on the drum and a smaller area near the cut-out that is big enough to surround the first end of the rigid element to contact the rigid element when the blade is mounted on the drum.
 12. The drum of claim 1, wherein the cut-out includes a cross section substantially of a triangle and a rectangle.
 13. The drum of claim 1, wherein the blade further comprises: a hollow body opened towards the band at the base of blade; and a plurality of inner ribs located inside the body.
 14. The drum of claim 13, wherein one end of one of the plurality of inner ribs defines a screw hole, and wherein the drum further comprises a screw in a corresponding opening on the cylindrical band.
 15. The drum of claim 13, further comprising a tab extending inwardly from the cylindrical band and being fittable with one of the ribs.
 16. The drum of claim 1, wherein a top side of the blade defines a plurality of outlets blade to obtain a rain effect in the washing process.
 17. The drum of claim 1, wherein a total length of the blade is smaller than a distance between two circular end walls of the drum.
 18. The drum of claim 1, wherein the blade comprises a plastic. 